1. Field of the Invention
The present invention relates to an image forming apparatus such as printing machine or copying machine having a plurality of process cartridges such as a photosensitive unit and a developer unit which can be attached to and detached from the main body of the apparatus.
2. Description of the Related Art
In printing machines and copying machines of the prior art wherein a plurality of process cartridges such as a photosensitive unit and a developer unit can be attached to and detached from the main body of the apparatus so that a user can easily service the apparatus including the replacement of the process cartridges, insertion ports and guide paths corresponding to the respective process cartridges have been provided on the main body of the apparatus in order to mount the process cartridges on the main body of the apparatus.
In the Japanese Patent Unexamined Publication No. 62- 272283, a copying machine is disclosed wherein a photosensitive unit and a developer unit can be attached to and detached from the main body of the apparatus, and an insertion port for the photosensitive unit and an insertion port for the developer unit are arranged adjacent to each other on the main body of the apparatus.
However, because a plurality of insertion ports and guide paths for the insertion of process cartridges are provided on the main body of the apparatus in the prior art, it is necessary to give indication of the name of cartridge that can be inserted prevent the insertion port in order to prevent the insertion of a wrong cartridge. This has increased the manufacturing cost and required the user to make sure of the cartridge name indicated at the insertion port before inserting the cartridge, thus resulting in very poor operability.